Parakaryon myojinensis, also known as the Myojin parakaryote, is a highly unusual species of single-celled organism known only from a single specimen, described in 2012.

The generic name Parakaryon comes from Greek παρά (pará, "beside", "beyond", "near") and κάρυον (káryon, "nut", "kernel", "nucleus"), and reflects its distinction from eukaryotes and prokaryotes.

The specific name myojinensis reflects the locality where the only sample was collected: from the bristle of a scale worm collected from hydrothermal vents at Myōjin Knoll (明神海丘,[2] 32°06.2′N 139°52.1′E / 32.1033°N 139.8683°E / 32.1033; 139.8683), about 1,240 metres (4,070 ft) deep in the Pacific Ocean, near Aogashima island, southeast of the Japanese archipelago.

Its discoverers suggested that additional specimens would be needed for culturing and DNA sequencing to place the organism in a phylogenetic context.

[1] British evolutionary biochemist Nick Lane hypothesized in a 2015 book that the existence of P. myojinensis could be the first known example of symbiogenesis outside eukaryotes, which could offer clues to the requirements for the development of complex life in general.